Sneezing, Coughing And Tickling Sensation In The Throat. Normal Chest X-ray. What Else Could Be Causing This?

I have throat tickling resulting sever coughing and sneezing . I get throat tickling at anytime, it could be at night wakes me up from deep sleep, it could be when sitting watching tv, it could be after a meal. sometimes tears come out of my eyes when i cough, my saliva becomes like okra veg, i have to keep on spitting out, i have to keep on clearing my throat. It has been over six months now since i had it, but I remember I used to sneeze every time I open books in library but never used to be serious like now. I m really frustrated, I visited two doctors so far one x- rayed my chest came out clean, the other doctor suggested throat spray etc.